(a) Technical Field
The present disclosure relates to a thermal management system for a fuel cell vehicle. More particularly, it relates to a thermal management system which may be miniaturized and may have a reduced weight by integrating thermal management parts in a fuel cell vehicle.
(b) Background Art
Generally, a fuel cell, being an apparatus directly converting fuel energy into electrical energy, is a system which is made up of a pair of electrodes consisting of an anode and a cathode having electrolytes disposed therebetween. As such, a fuel cell obtains electricity and heat by an electrochemical reaction of ionized fuel gas.
One type of fuel cell is a polymer electrolyte membrane fuel cell. In particular, polymer electrolyte membrane fuel cells may have a high current density, a low operation temperature, a less corrosion and electrolyte loss, and a high output density. These types of fuel cells may also be modularized due to their simple structure. Therefore, a study for applying the polymer electrolyte membrane fuel cell as a power source of a vehicle has been actively conducted over the past few decades.
At present, a fuel cell system applied to a fuel cell vehicle includes a fuel cell stack generating electric energy from an electrochemical reaction of a reaction gas, a hydrogen supply apparatus configure to supply hydrogen, as a fuel, to the fuel cell stack, an air supply apparatus configured to supply air including oxygen as an oxidizer required for the electrochemical reaction to the fuel cell stack, a thermal management system configured to optimally control an operation temperature of the fuel cell stack by emitting/dissipating heat, which is an electrochemical reaction byproduct of the fuel cell stack, away from the stack, and the like.
In a fuel cell system, the efficiency of a fuel cell is approximately 50% and therefore as much energy as is output is also emitted as heat. As such, a large amount of heat is generated during the use of the fuel cell. In particular, a polymer electrolyte membrane fuel cell should be maintained at a temperature t within a range of approximately 25° C. (normal temperature) to 80° C. in order to allow for a sufficient lifespan and performance and to obtain a stabilized output state.
For example, a fuel cell stack in the fuel cell system typically generates electrical energy from the electrochemical reaction of hydrogen and oxygen and emits heat and water as the reaction byproducts. Therefore, to prevent the temperature of the fuel cell stack from rising in the fuel cell system, the thermal management system is employed typically to cool the fuel cell stack and other components within the system.
Generally, thermal management systems generally cool the fuel cell stack by circulating water through a cooling water channel within the fuel cell stack in order to maintain the fuel cell stack within an optimal temperature range.
In particular, a thermal management system generally includes a cooling water line connected between the fuel cell stack and a radiator to circulate the cooling water, a bypass line and a 3-way valve installed to bypass the cooling water around the radiator, a pump that pumps the cooling water a through the cooling water line, a heater that heats the cooling water, and the like.
However, in thermal management systems for a fuel cell vehicle, parts are generally individually developed and therefore the number of parts and man-hours required to assemble the thermal management system are increased. Additionally, these systems typically generate a lot of dead space. This makes it very difficult to achieve the required miniaturization and weight reduction of the thermal management system required by vehicle manufactures while still securing the performance and durability of the thermal management system.
For example, it is difficult to reduce the connection space between pump-pipe and the 3-way valve. This connection spaces increases the differential pressure due between these parts as well as reduces the flow rate and cooling performance, etc.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.